GLNs

GLNs, or Global Location Numbers, are 13-digit identifiers used within the GS1 system to uniquely identify physical locations and legal entities in supply chains. They are intended to enable precise, unambiguous reference to places such as factories, warehouses, distribution centers, stores, and corporate offices, as well as to distinguish different organizational units. GLNs do not carry address data themselves; they function as keys that can be linked to address and contact information in master data systems.

The structure of a GLN starts with the GS1 company prefix allocated by a national GS1 member organization, followed by a location reference that distinguishes one location from another within the same legal entity. The final digit is a check digit calculated using the GS1 Mod 10 algorithm to help detect input errors. Because the company prefix length varies, GLNs are a flexible way to accommodate different organizational sizes while maintaining a fixed 13-digit total length.

GLNs are used in various GS1 standards and processes, including barcoding and electronic data interchange. In GS1-128 barcodes, for example, the GLN can be encoded with Application Identifier 414. They are commonly employed in master data, order processing, shipping notices, and invoicing to ensure that the correct location or entity is referenced throughout the supply chain. GLNs are globally administered by GS1 through its member organizations, ensuring uniqueness within the GS1 system. They should not be confused with GTINs, which identify products rather than locations.